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Finding the Fourth Proportional to 208.31, 287.38 and 142.70

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Solution

The fourth proportional to 208.31, 287.38 and 142.70 is: 196.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.31 : 287.38 = 142.70 : x
  2. Step 2: Convert to fraction form
    208.31/287.38 = 142.70/x
  3. Step 3: Cross multiply
    208.31x = 287.38 × 142.70
  4. Step 4: Simplify right side
    208.31x = 41,009.13
  5. Step 5: Solve for x
    x = 41,009.13/208.31
  6. Step 6: Final answer
    x = 196.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.